1. Field of the Invention
The present invention relates to an apparatus for removing attachments deposited on underwater structures; particularly, relating to an apparatus for removing marine organisms deposited on underwater structures, such as stanchions extending underwater, particularly in the sea, and for preventing possible deposits thereafter.
2. Prior Art Statements
As the prior art for removing marine organisms deposited on piles that support marine constructions, such an apparatus is known that is constituted of a metal wire with buoyant pieces that floats around piles on the surface of the sea where with the aid of wave power the wire makes contact with marine organisms in order for them to be removed. (See Japanese Patent Preliminarily Publication No. 10-219652)
Another apparatus is known which comprises a plurality of hollow bodies each respectively having lugs at both ends, a protective ring provided on each hollow body in a rotatable manner, and a socket ring further provided on the protective ring in a fixed manner. The hollow bodies each having a protection ring and a socket ring are connected together to make a large circle, and set out around structures, such as piles, so that the apparatus makes contact with the surface of the structures with the aid of wave force to remove attachments, such as marine organisms, deposited thereon (See Japanese Patent Preliminarily Publication Nos. 2000-8339 and 2003-1998). When the apparatus makes contact with the structures, the protective ring and the socket ring rotate in a united manner, so that the impact when the apparatus impinge upon the structures is absorbed and thus the wear of both the structures and the apparatus is decreased. At the same time, the apparatus shows excellent performance in removing the attachments deposited on underwater structures. In this manner, it is an elementary requirement that the part of the apparatus where contact is made with the structure is rotatable, in order to improve the durability and the deposit removing ability of the apparatus.
These conventional apparatuses for removing attachments deposited on structures are set out in the water such that the apparatus surrounds underwater structures, such as piles. The apparatus makes repeatedly contact with the surface of the structures; resulting in deposits, such as marine organisms, being removed in several weeks. By leaving the apparatus thereafter, further deposits of marine organisms on the surface of the structure can be prevented in the future.
The apparatus for removing deposits disclosed in Japanese Patent Preliminarily Publication No. 10-219652 is arranged such that a wire having some floating bodies makes contact with the surface of steel piles or concrete piles in order to remove the attachments deposited thereon. Since the apparatus is left for a comparatively long term, it is required to use metal wire, such as that made of stainless steel. However, galvanic corrosion occurs on such metal wire after setting it out underwater, and it therefore cannot stand long term use. Further, when the wire is partially damaged, for example, by corrosion, it is necessary to change the wire as a whole, requiring hefty work at great expense. Furthermore, the metal wire should be hard and thin which causes abrasion to the concrete piles over an extended period of time deteriorating the strength thereof.
In the apparatus for removing deposits disclosed in Japanese Patent Preliminarily Publication Nos. 2000-8339 and 2003-19998, the rotatable protection ring and the socket ring are provided on the outer surface of each hollow body to be connected together. These members, i.e. the protection ring, the socket ring and the hollow body, need to be separately prepared and then assembled. This makes the manufacturing cost of the apparatus high, and the assembly work complicated. When using the apparatus, plural members are connected together and it is necessary to prepare many of the apparatuses at a single site, therefore manufacturing costs increase and heavy assembly work is required. Since the apparatuses are connected together with the aid of nuts and bolts, and on average 15˜40 apparatuses are used at a single site, a large amount of labor is required.
Further, as stated above, plane lugs are provided at both ends of the hollow body; and the bodies are connected together in such a manner that the lugs are superimposed on one another with the aid of nuts and bolts. However, in such a construction, when an outer force is applied to the superimposed lugs in a perpendicular direction, it is difficult to allow release of the outer force. This causes the problem of the apparatus becoming brittle in structure. Furthermore, a soft vinyl chloride is used for the material of the apparatus, causing a toxic gas to generate freely when the apparatus is incinerated for disposal.